package com.xgp.pc;

/**
 * 线程之间的通信问题：生产者和消费者问题! 等待唤醒 通知
 * 线程交替问题 A  B 操作同一个变量  num = 0
 * A num+1
 * B num-1
 * @author 薛国鹏
 */
@SuppressWarnings("all")
public class A {
    public static void main(String[] args) {
        Data data = new Data();

        new Thread(() -> {for(int i = 0;i < 10;i++) {
            try {
                data.increment();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        },"A").start();
        new Thread(() -> {for(int i = 0;i < 10;i++) {
            try {
                data.decrement();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        },"B").start();
        new Thread(() -> {for(int i = 0;i < 10;i++) {
            try {
                data.increment();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        },"C").start();
        new Thread(() -> {for(int i = 0;i < 10;i++) {
            try {
                data.decrement();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        },"D").start();
    }
}

/**资源类**/
class Data {
    private int number = 0;

    /**
     * 判断等待、业务、通知
     */

    //+1
    public synchronized void increment() throws InterruptedException {
        while (number != 0) {
            // 等待
            this.wait();
        }
        number++;
        System.out.println(Thread.currentThread().getName() + "=>" + number);
        // 通知其他线程，我+1完毕了
        this.notifyAll();
    }
    //-1
    public synchronized void decrement() throws InterruptedException {
        while (number == 0) {
            //等待
            this.wait();
        }
        number--;
        System.out.println(Thread.currentThread().getName() + "=>" + number);
        // 通知其他线程，我-1完毕了
        this.notifyAll();
    }
}